At Google I/O in May, Google Product Manager, Jeffery Jose, announced not only that page experience update was coming to desktop, but also that Sites built with signed exchanges will be pre-fetched by Google. It is expected that the new page experience update will begin in mid-June 2021.
By prefetching and storing the pages on the user’s browser, they are ready to be loaded as soon as the user clicks on the result, making loading near-instantaneous. In addition, Google maintains a network of fast cache servers spread around the globe, which you now have access to without additional cost.
On Signed Exchanges (SXGs), Google Search will now crawl, cache, and prefetch them when applicable. It can improve Largest Contentful Paint (LCP) and Page Performance #GoogleIO pic.twitter.com/xF4Y8Fsu8x— Samuel Lavoie 💉 (@samuellavoie) May 18, 2021
After offering publishers this as an option in 2019, Google added signed exchange issues to Search Console recently.
It’s worth noting that Google had a Chrome-based prefetch mechanism in 2011.